Cutting tool



July 11, 1961 Filed Aug. 21, 1957 T. A. KENNARD CUTTING TOOLSheets-Sheet 1- INVENTOR.

7/70/7704 A. Ken/70rd July 11, 1961 1-. A. KENNARD CUTTING TOOL FiledAug. 21, 1957 -vsb iya 2 Sheets-Sheet 2 United States Patent- 2,991,834CUTTING TOOL Thomas A. Kennard, Box 723, Jennings, La. Filed Aug. 21,1957, Ser. No. 679,332 Claims. (Cl. 166- 55.7)

This invention relates to well tools and more particularly to tools forcutting off and removing from a well an upper section of a string ofpipe and to an assembly for anchoring tools or the like in a well.

It is an object of this invention to provide a new and improved tool forremoving fish from a well with a single tool which cuts and washes awayinterfering material, then cuts free a section of pipe and then removesthe cut section from the well; all in one run.

Another object is to provide a tool for removing fish from a well inwhich the fish maybe released at any time and after releasing the fishthe tool is ready for reuse and may be moved to another location.

Another object is to provide a tool which, if the fish cannot be pulledafter cutting, can be released and a cut made at a shallower depth; thenwhen the fish is pulled the tool can be released and anchored to thestuck fish to pull all cuts out of the hole the same trip.

Another object is to provide a cutting tool for well pipe in which thetool is anchored to the pipe during the cutting action and in which thetool may be freed from the pipe at any time without damage to the tool.

Another object is to provide a cutting tool for well pipe in which thecutting knives may be retracted at any time and held in anout-of-the-way position to permit movement of the tool in the pipe.

Another object is to provide a cutting tQol for well pipe employing aslip assembly for anchoring the tool to the pipe in which downwardmovement of the' string from which the tool is suspended moves the slipsinto an inoperative position to permit moving the tool upward.

Another object is to provide a setting assembly for anchoring a tool toa well pipe including a slip assembly on a mandrel in which movement ofthe mandrel downward relative to the slip assembly after the settingassembly has anchored the tool to a pipe renders the an choring assemblyinoperative to permit release of the pipe by the tool. 1

Other objects, features and advantages of this invention will beapparent from the drawings, specification and claims.

In the drawings wherein like referenced numerals indicate like parts:

FIGS. 1, 2, and 3 are schematic views in section of a tool constructedin accordance with this invention and showing in FIG. 1 the position ofthe parts as the tool is run into the hole, in FIG. 2 the slip assemblyin the process of being anchored, and in FIG. 3 the tool anchored in apipe and cuttingfree an upper section of pipe; and

FIGS. 4A, 4B, and 4C are continuation views partly in longitudinalelevation and partly in longitudinal cross section of a preferred formof this invention.

The tool illustrated in the drawings includes a mandrel indicatedgenerally at which extends the full length of the tool and carriesthereon a sleeve indicated generally at 11. Carried by one of themandrel and sleeve, preferably the sleeve as illustrated, are aplurality of cutters or knives 12 (FIG. 4B) which are'in retractedposition with the mandrel and sleeve in one telescoped position. Thecutters are extended .by a resiliently loaded actuator 13 when themandrel and sleeve are in another relative telescoped position. At theupper end of the tool (FIG. 4A) there is provided a settin g'asse nblyin- 2. dicatcdgenerally at 1 4 for anchoring the tool to. a fish. Thesetting assembly provides a stop limiting. movemen-t of the sleeve 11 tocause change of the relative telescoped position between the mandrel andsleeve upon raising of the mandrel after the setting assembly hassecured the tool to a pipe. As will be explained in detail below thesetting assembly may be released at will of the operator to permitchanging the position of the tool in the fish or completely withdrawingthe tool. The mandrel 10 is preferably hollow as shown to provide afluid passageway to maintain circulation and washv interferi'ng materialaway from the fish; The lower. end of. the tool is provided with a bitindicated generally at 15 for cutting away interfering material topermitthe tool to reach the fish.

The mandrel 10 includes. an upper section 16 and a lower section 17.Each of sections 16 and 17 is tubular in form to provide a bore 18extending through the mandrel for maintaining circulation through thetool. The mandrel 10 is suspended from head sub 19; which is the lowerend of a conventional string of pipe used in running tools of this type.i i

The setting assembly 14 is preferably carried on the upper section 16.The setting assembly includes a slip carrier 21 surrounding uppermandrel section 16 aiid slidably and rotatably mounted'thereon. Aplurality of drag springs 22 are mounted on the slip carrier 21 extendbetween carrier 21 and the drag spring cage23 which is also slidably androtatably mounted'on the upper mandrel section :16. The drag springs 22engage the wall of a pipe into which the tool is and frictional-1yresist movement of the slip carrier relative to this pipe. This permitsrelative shifting between the slip carrier. and mandrel under thecontrol of the operator atI-the surface. Depending from the slip carrierare a plurality offslip fingers 24. The lower end of fingers 24 areprovided with teeth 23 for gripping the pipe or fish to be removed'whe nthe slip fingers are expanded.

For purposes of selectively. expanding th slip fingers 24 cone 26 isprovided. Cone '26 isrotatably and slidably mounted on the upper mandrelsection 16 and iscoufined between theupper end of the sleeve 11 andfashoulder 27 on the upper mandrel section 16. It will be readily apparentthat moving the cone '26 behind the slip fingers 25 will force the ,slipfingers 25 outward and into engagement with the wall of the fish.

Shoulder 27 also acts as a jar 'knocker to drive the cone from behindthe slips when disengaging thetodl from a pipe. i

The slip fingers are held in an out-of-.the=way position duringwithdrawal of the tool and: are moved into a position to be engaged bythe cone on setting of the tool by a short sectionof complementarythreads 28 on the slip finger and the upper mandrel section 16. Thethreads are raised on both the slip fingers and mandrel section and donot interfere with the operation of the setting assembly except whenthey are engaged. 'Ihe upper flanks 28a of the threads on the mandreland the complementary lower flanks 28b of the threads on the slipfingers are inclined slightly from a plane perpendicular tothe axis ofthe mandrel. These flanks provide stops which prevent the slip fingersmoving downwardly after the thread system has been engaged except uponrotation of the mandrel relative to the slip fingers. On the other handthe upper flanks 28c of the thread on' the slip fingers and the lowerflanks 28a of themand re l threads are inclined at a substantial anglefrom snails perpendicular to the axis of the mandrel to permit thisthreads of the slip fingers .to slide upward over threads on themandrel. Thus on going in the hole the slip carrier will always moverelatively upwardly with an inclined flank 28e or jump thread at thelower end of the thread system which prevents engagement of the threadsystem as the mandrel moves upwardly relative to the slip carrier untilall threads on the mandrel have passed the jump thread. This permits allthreads of the thread system to engage simultaneously. This jump threadsystem insures that all of the threads of the system are engaged andthere is no danger of pulling the mandrel up through the slip fingers.Also the operator will know that only a predetermined number ofrevolutions are necessary to disengage the mandrel and slip fingers.Once the mandrel has been turned through this number of revolutions theslip fingers are disengaged and have been moved downwardly into aposition to be engaged by cone 26 as the mandrel is raised.

Referring now particularly to FIG. 4B, the sleeve 11 includes an uppersplined section 29 and a lower cutter body section 31. The lower mandrelsection 17 has at its upper end a splined nut 32 which cooperates withthe splined sleeve section 29 to impart rotation from the mandrel to thesleeve. The splined portion 29a of sleeve 29 terminates at its upper andlower ends at stops 29b and 29:: respectively which are engaged by thesplined jar nut 32 to limit relative movement of the sleeve and mandrel.With the nut 32 in engagement with the stop 290, the knives 12 are intheir retracted position. With the nut 32 in engagement with the upperstop 29b the knives are in operating position. A direct pull may beimparted from nut 32 to cone 26 which rests on the top of the splinedsleeve section to drive the cone firmly home behind the slip fingers.

The cutter body 31 is slotted as at 33. Knives 12 are pivotally mountedon the cutter body in slots 33 for radial movement into engagement witha pipe to be cut. Relatively weak knife springs 34 bias each of theknives 12 toward fully retracted position.

As the mandrel moves upwardly in sleeve 11 expansion spring 35 for thesleeve 11 is collapsed. This spring returns the sleeve and mandrel totheir relative telescoped position as viewed in FIGS. 4A, 4B, and 40upon lowering of the mandrel relative to the sleeve.

A resiliently urged actuator is provided for moving the knives radiallyinto contact with the pipe to be cut. Preferably the resilient means isprovided by a feeder spring 36.

To insure that the spring 36 is inoperative to force the actuator 13into engagement with the cutters 12 when the tool is not anchored in thepipe, there is provided an actuator release which prevents operation ofthe actuator until the mandrel is moved upwardly relative to the sleevefrom the position shown in FIG. 4B. In the form of the inventionillustrated the actuator release is provided by a shoulder 37 on themandrel which engages an actuator release plug 38 on the actuator andprevents upward movement of the actuator. As the mandrel is pulledupwardly relative to the sleeve the shoulder 37 is moved into anout-of-the-way position and the spring urges the actuator 13 behind thecutters 12. The wedge 13a on the actuator forces the cutters radiallyinto engagement with the pipe to be cut.

It will be noted that the feeder spring 36 is supported on a lifting nut39 secured to the lower end of the mandrel 10. Thus the force behind theknives can be varied by controlling the relative positions of themandrel and sleeve. On the other hand the positive stop provided bycontact of the spline nut 32 with the upper stop 29b in the splineportion of the sleeve will limit the amount of force which can beapplied to drive the cutters radially.

Depending from the lifting nut 39 is a tail pipe or pack off tube 41which has a sliding seal with the pack ofi sub 42. Sub 42 depends fromthe cutter body 31. The pack off sub 42 carries at its lower end the bit15. With this arrangement a positive seal is provided for forcing fluidcirculated through the mandrel out the lower end of the bit for ajetting and washing action on the material interfering with the movementof the tool into position within the fish.

Operation of the tool is illustrated in FIGS. 1, 2, and 3. In FIG. 1 thetool is being run in the hole. The slip as sembly, dueto the friction ofdrag springs 22, is at its uppermost position and abutting the head sub19. In this position the cone 26 is removed from the slip fingers 24 andthe slip fingers do not interfere with the running of the tool. When thetool reaches the fish it may be rotated to permit bit 15 to drillthrough interfering material. Drilling fluid may be circulated throughthe tool to wash away cuttings in the usual manner.

After the tool is lowered into the fish the desired distance the pipestring on which the tool is mounted is raised. This condition isillustrated in FIG. 2. As the mandrel moves upward the drag springs 22hold the slip assembly against movement and the mandrel moves upwardrelative to the slip assembly until the thread system 28 engages. Itwill be recalled that jump thread 28c holds the thread system out ofengagement until all threads are in position to engage and then permitsthe threads to engage. From FIG. 2 it will be noted that at this timethe slip segments and the cone are still not in engagement. To move theslips into a position to be engaged by the cone. the operator rotatesthe drill string counterclockwise a sufiicient number of turns to movethe slip assemblydownward relative to the mandrel until the threadsystem 28 is disengaged. At this time the cone 26 will be positionedjust below the slip segments. If desired the design may be such thatinitial engagement is provided between the slip segments and the cone.In either case as soon as the thread system 28 is disengaged theoperator again raises the string to raise the mandrel and force the conebehind the slip segments. The slip fingers are driven into the wall ofthe pipe to anchor the tool relative to the pipe. Continued upwardmovement is then exerted on the mandrel and the mandrel will moveupwardly through the sleeve 11 until the mandrel and sleeve are in therelative telescoped position illustrated in FIG. 3. At this time theactuator release 37 will be in out-of-the-way position and the feederspring 36 will move the actuator behind the cutters and force themradially into the wall of the pipe to be cut. With the tool in theposition illustrated in FIG. 3, rotation of the tool will rotate theknives and the fish will be cut in two as illustrated in FIG. 3.

After the cut has been completed the spring may be raised to bring thetool and the fish to the surface.

If after the tool is engaged in the pipe and cut is commenced, it isdesired to release the fish this may be easily accomplished. Oneinstance in which it would be desired to release the fish is when thefish cannot be pulled. In this case it would be desirable to be able torelease the fish and raise the tool to a shallower depth and make anadditional cut. This is possible with the tool of this invention as itmay be released without damage merely by lowering the mandrel throughthe sleeve to the posi tion shown in FIG. 2. With the tool in thisposition the spline nut 32 engages stop 29c and upward force on the cone26 is removed. Then by jarring down on the mandrel the mandrel shoulder27 (FIG. 4A) will drive the cone out from under the slip fingers.

After the cone is jarred free, further lowering of the mandrel relativeto the slip assembly will cause the threads on the mandrel to passthrough the threads on the slip fingers and the parts of the tool willagain assume the position illustrated in FIG. 1. The tool may then beraised and the parts will then assume the position illustrated in FIG. 2with the thread system engaged. However as the cone is not in engagementwith the slip fingers the tool may be raised to a shallower depth andreset in the manner above explained. A second cut may then be made andthe fish pulled free. When the top section of the fish is pulled free itmay be released and the tool run in again to the position ofapproximately the first cut and the tool again set in the section ofpipe above the first cut but below the second out. As the mandrel islifted this time the fish may come free; if not another section of fishis cut oif and the operation repeated until the fish is freed to thedesired depth. Then the tool may be pulled to the surface while securedto the lowermost fish bringing with it all of the preceding cuts.

The foregoing disclosure and description of the invention isillustrative and explanatory thereof and various changes may be madewithin the scope of the appended claims without departing from thespirit of this invention.

What is claimed is:

1. A pipe cutter comprising, a tubular mandrel adapted to be secured tothe lower end of a string of pipe, an outer sleeve mounted on themandrel for limited sliding movement, resilient means urging the sleeveupward relative to the mandrel, cutters carried by the sleeve, meansurging the cutters radially outward when the sleeve and mandrel aremoved relative to each other against said resilient means, a conerotatably and slidably positioned on the mandrel at the upper end of thesleeve, a slip assembly including a slip carrier slidably mounted on themandrel above the cone and having a plurality of slip fingers dependingfrom the carrier which when expanded by the cone engage the wall of apipe in which the assembly is run to anchor the assembly, drag springson the slipassembly, a short section of threads on the slip assembly andmandrel which when engaged hold the slips above the cone and when themandrel is screwed upward through the slip assembly releases the slipsfor engagement with the cone, said threads ineffective to prevent theslips moving away from the cone, and means eifective upon lowering ofthe mandrel for forcing the cone out of engagement with the slipassembly.

2. A setting assembly for a well tool comprising, a tubular mandreladapted to be secured to the lower end of a string of pipe, a conerotatably and slidably mounted on the mandrel, a slip assembly includinga slip carrier slidably mounted on the mandrel above the cone having aplurality of slip fingers depending from the carrier and when expandedby the cone engaging the wall of a pipe in which the assembly is run toanchor the assembly, drag springs on the slip assembly, and a shortsection of threads on the slip assembly and mandrel which when engagedhold the slip fingers above the cone and when the mandrel is screwedupward through the slip assembly releases the slip fingers forengagement with the cone.

3. A setting assembly for 'a well tool comprising, a tubular mandreladapted to be secured to the lower end of a string of pipe, a conerotatably and slidably mounted on the mandrel, a slip assembly includinga slip carrier slidably mounted on the mandrel above the cone having aplurality of slip fingers depending from the carrier and when expandedby the cone engaging the wall of a pipe in which the assembly is run toanchor the assembly, drag springs on the slip assembly, a short sectionof threads on the slip assembly and mandrel which when engaged hold theslip fingers above the cone and when the mandrel is screwed upwardthrough the slip assem- 6 bly releases the slip fingers for engagementwith the cone, and means elfective upon lowering of the mandrel forforcing the cone out of engagement with the slip fingers.

4. A setting assembly for a well tool comprising, a mandrel, a conemounted on the mandrel, a slip carrier slidably mounted on the mandreland having a plurality of slip fingers depending from the carrier andwhen spread by the cone engaging the wall of a pipe and anchoring thetool, drag springs on the slip carrier, a short section of co-actingthreads on the slip fingers and mandrel, the flanks of said threadsformed at an angle permitting the threads of the slip fingers to moveover the threads on the mandrel when the mandrel is moved downwardthrough the slip fingers, said threads when engaged preventing themandrel from moving upward through the slip fingers to hold the slipfingers out of engagement with the cone, said threads released to permitengagement of the fingers and cone by relative rotation of the mandreland slip fingers.

5. A pipe cutter for wells comprising, a tubular mandrel adapted to besecured to the lower end of a string of pipe, a concentric sleevenon-rotatably carried by the lower end of the mandrel and mounted forlimited sliding movement, resilient means urging the sleeve toward theupper end of the mandrel, cutters mounted on the sleeve for radialmovement, relatively weak resilient means urging the cutters in oneradial direction, an actuator mounted in an annulus between the mandreland sleeve and having wedge means cooperable with the cutters to urgethem radially, relatively strong resilient means biasing the actuatortoward the cutters to urge the cutters in the other radial direction, anactuator release carried by the mandrel effective to hold the actuatorout of engagement with the cutters when the mandrel is at the lower endof its travel relative to the sleeve and releasing the actuator as themandrel moves upward relative to the sleeve, a cone rotatably andslidably positioned on the mandrel at the upper end of the sleeve, aslip assembly including a slip carrier slidably mounted on the mandrelabove the cone and having a plurality of slip fingers depending from thecarrier which when expanded by the cone engage the wall of a pipe inwhich the assembly is run to anchor the assembly, drag springs on theslip assembly, a short section of threads on the slip assembly andmandrel which when engaged hold the slips above the cone and when themandrel is screwed upward through the slip assembly releases the slipsfor engagement with the cone, said threads ineffective to prevent theslips moving away from the cone, and means effective upon lowering ofthe mandrel for forcing the cone out of engagement with the slipassembly.

References Cited in the file of this patent UNITED STATES PATENTS1,867,289 Ventresca July 12, 1932 1,941,703 Martois Jan. 2, 19341,992,933 Baker et al. Mar. 5, 1940 2,202,986 Ellis June 4, 19402,203,011 Ellis et al. June 4, 1940 I 2,604,945 Page July 29, 19522,623,593 Pennington et al Dec. 30, 1952 2,659,434 Osmun Nov. 17, 19532,665,765 Baker Jan. 12, 1954

